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Which one is better to use, Var, Let or Const?

Hi everybody! I was wondering about that, which one is better to use and why? All the courses about JS is with var, but then when I check about info in sites like w3school, freecodecamp, etc, I see 'let' everywhere.

Happy new year to all!

2 Answers

Clayton Perszyk
Clayton Perszyk
Treehouse Moderator 48,603 Points

for variable declarations let is preferred to var as it creates block scope, eliminating troublesome hoisting errors. If you don't want the value to change, use const.

This article provides additional info:


Hello Federico! I agree with Clayton.

Previously people used to use var, however, it is considered to be bad practice now. The var keyword causes many scope errors that annoy a lot of developers. This is why they made the let and const keywords.

let is very similar to var however, it does not cause the scope errors that var did. let can also be changed.

const is short for constant, which is a variable that you do not want to change. A variable that will have a constant value.

I hope this helps!